"She has been in it ever since and she raised her daughter Lisa Marie in it."

Her daughter, 49, has since quit the religion in 2014, which the source says was a contributing factor to Priscilla's exit.

"Lisa Marie leaving made it hard for Priscilla," the insider continued. "They are very close as a family and leaving the Church has been a family decision."

Scientology was founded by sci-fi writer L. Ron Hubbard in 1955.

Elvis and Priscilla Presley: The King's iconic marriage in pictures

Fri, October 14, 2016

Elvis and Priscilla met on September 13, 1959 during a party at Elvis' home in Germany, while he was serving in the Army. Express Pictures looks back on their iconic relationship and marriage that captured the attention of the world.